/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.context.support;

import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Simple implementation of {@link org.springframework.context.MessageSource}
 * which allows messages to be registered programmatically.
 * This MessageSource supports basic internationalization.
 *
 * <p>Intended for testing rather than for use in production systems.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 */
public class StaticMessageSource extends AbstractMessageSource {

    /**
     * Map from 'code + locale' keys to message Strings.
     */
    private final Map<String, String> messages = new HashMap<>();

    private final Map<String, MessageFormat> cachedMessageFormats = new HashMap<>();


    @Override
    protected String resolveCodeWithoutArguments(String code, Locale locale) {
        return this.messages.get(code + '_' + locale.toString());
    }

    @Override
    @Nullable
    protected MessageFormat resolveCode(String code, Locale locale) {
        String key = code + '_' + locale.toString();
        String msg = this.messages.get(key);
        if (msg == null) {
            return null;
        }
        synchronized (this.cachedMessageFormats) {
            MessageFormat messageFormat = this.cachedMessageFormats.get(key);
            if (messageFormat == null) {
                messageFormat = createMessageFormat(msg, locale);
                this.cachedMessageFormats.put(key, messageFormat);
            }
            return messageFormat;
        }
    }

    /**
     * Associate the given message with the given code.
     *
     * @param code   the lookup code
     * @param locale the locale that the message should be found within
     * @param msg    the message associated with this lookup code
     */
    public void addMessage(String code, Locale locale, String msg) {
        Assert.notNull(code, "Code must not be null");
        Assert.notNull(locale, "Locale must not be null");
        Assert.notNull(msg, "Message must not be null");
        this.messages.put(code + '_' + locale.toString(), msg);
        if (logger.isDebugEnabled()) {
            logger.debug("Added message [" + msg + "] for code [" + code + "] and Locale [" + locale + "]");
        }
    }

    /**
     * Associate the given message values with the given keys as codes.
     *
     * @param messages the messages to register, with messages codes
     *                 as keys and message texts as values
     * @param locale   the locale that the messages should be found within
     */
    public void addMessages(Map<String, String> messages, Locale locale) {
        Assert.notNull(messages, "Messages Map must not be null");
        messages.forEach((code, msg) -> addMessage(code, locale, msg));
    }


    @Override
    public String toString() {
        return getClass().getName() + ": " + this.messages;
    }

}
